Explosive



Patented Apr. 27, 1937 UNITED STATES PATENT OFFICE EXPLOSIVEY fornia No Drawing.

10 Claims.

This application is a continuation in part of our copending application Serial No. 673,023, filed in the United States Patent Ofiice May 26, 1933, and the invention relates to blasting powders containing as an ingredient a composition of matter consisting. mainly of nitronaphthalene and to the special preparation of such nitronaphthalene.

An object of the invention is the preparation of an explosive for blasting and destructive pur- DOSES.

Another object of the invention is the production of a blasting powder useful for subterranean mine work.

Another object of the invention is theproduction of an explosive the products of explosion of which are free of poisonous gases and gases which have a tendency to produce headache or other illness.

Another object of the invention is the pro.-

duction of a blasting powder the explosion of which is fiashless, even when occurring in the dark.

Another object of the invention is the production of blasting powder capable to a high degree of shattering the material in which it is exploded, and which is sufficiently active to be highly useful without being so active as to be dangerous in handling.

Other objects of the invention are the production of a blasting powder which will not. ex-

plode on being heated, or on being contacted with a flame, or by impact; which will not freeze, and which requires fulminate of mercury or other suitable detonator to explode it.

3 The above are some of the ultimate objects of the invention, and special objects of the invention include the production of a special composition of matter including nitronaphthalene useful in making blasting powders and which helps to ac- 40 complish the above mentioned general objects, as

well as this special composition itself.

Other objects of the invention will become apparent on reading this specification.

For preparing the explosive or blasting powder,

45 we first nitrate naphthalene, using as raw material for this reaction pure naphthalene, which is commercially obtainable as naphthalene flakes. We pour into a vessel one hundred (100) fluid ounces of 40 degree Baum nitric acid. Vapor 5 starts coming off on doing so, and after allowing an interval, say, about one-half minute, we pour forty (40) fluid ounces of 66 B. sulphuric acid into the nitric acid in the tank without stirring, since stirring causes poor results. The mixture 65 of the acids develops some heat which, however,

Application July 17, 1934, Serial No. 735,566

is insufiicient for the desired result and heat is supplied preferably by surrounding the vessel with a water bath, the water of which is boiled to heat the acids to about the temperature of boiling water, that is, about 100 C. When the acids 5 are at this temperature, forty-five (45) avoirdupois ounces of the flake (or other pure) naphthalene are added, the flake being preferable on account of the large surface area thereof. This addition is made without stirring since this would 10 cause frothing or boiling, which is to be avoided. The reaction on adding the naphthalene generates heat so that about five minutes after the addition of the naphthalene the heat supplied to the water bath may be cut off, since the reaction heat 15 will then be sufficient to carry on the reaction properly.

The proportions above given should be very closely adhered to for the best results since a deviation therefrom of as much as one-half of one 20 per cent. with respect to any two of the three ingredients will result in an inferior or even a useless product.

It is to be noted, however, that the nitric acid used may run as low as B., but the lower the 25 strength thereof, the slower will be the nitrating action, which ordinarily requires, about seven hours for B. nitric acid and an additional hour for 35 36. nitric acid. We prefer the 40 B. nitric acid for this reason, as well as for the 30 reason that it yields a more desirable product.

As stated above the reaction mass is not stirred on adding the naphthalene to the acids nor is it stirred thereafter since even towards the end of the reaction stirring causes frothing or boiling 5 over. Golden-brown fumes appear as long as the nitrating reaction lasts, and absence thereof may be taken as the indication of the end of the reaction. Such fumes are no longer present ordinarily after about six or seven hours, and 40 there will then be two layers in the reaction vessel, a lower yellow aqueous layer and an upper orange-colored oily layer. The layers are separated as by siphoning or drawing off the aqueous layer from below the oily layer, and the oily layer is then washed. It is common practice in the explosives industry to wash the nitro-compounds or nitrated compounds resulting from the nitraj tion of organic compounds very thoroughly to remove the last traces of acid or whatever watersoluble material may adhere to or be associated with the product of nitration as a matter of safety in order to prevent premature or accidental explosion. I

The process of nitration indicated above may,

of course, be varied to some degree with respect to the various reaction conditions, but we prefer to follow the specific procedure indicated for best results, taking all conditions into consideration.

One of the features of novelty of this invention is that while we wash the product of the nitrating reaction, yet we do not wash it absolutely thoroughly or completely, as will be explained more fully hereinafter. The product of the nitrating reaction, that is, the oily layer, will have an acidity corresponding about to 1 calculated as sulphuric acid, and empirically stated, we may say that we prefer to wash until such acidity is reduced to about A of 1%, without limiting ourselves absolutely to this latter figure.

The product of nitration which we have so far described and which consists mainly of nitronaphthalene along with certain amounts of certain kinds of by-products we will hereinafter designate as special nitronaphthalene for the sake of brevity.

Our special nitronaphthalene is mixed with other ingredients, preferably picric acid and sodium nitrate, to form the finished blasting powder. A mixture of picric acid and sodium nitrate forms a good explosive, but such a mixture is a little too sensitive, that is, it is apt to explode at an undesired time. Furthermore, it is difficult to obtain a homogeneous mass of these two ingredients. The presence of nitronaphthalene aids very much in obtaining a homogeneous mass, but if the nitronaphthalene be pure, it dampens the sensitivity too much.

We have discovered that our special nitronaphthalene not only simplifies the making of a homogeneous mixture of picric acid and sodium nitrate, but results in a blasting powder having the desired degree of sensitivity, such degree of sensitivity being variable to some extent more or less inversely with the degree of washing above referred to; so that our discovery comprises the manufacture of a blasting powder, the blasting powder itself having generally the most desired degree of sensitivity and being one in which such sensitivity may be varied for special purposes.

The special nitronaphthalene made according to our preferred method seems to analyze about 17% of di-nitronaphthalene, the remainder, with the exception of the small amount of by-products, being mono-nitronaphthalene. We do not, however, wish to limit ourselves to just these proportions nor particular substances since we are not absolutely certain of the chemical analysis; and, furthermore, there are other methods of nitrating well known in the art in one of which, for example, sodium nitrate is used as the source of nitrogen and according to which naphthalene may be nitrated. Our invention in a broader aspect includes such a nitronaphthalene or mixture of nitronaphthalenes so produced provided that the by-products are not all washed out.

The results of the nitrating step are not only a nitration but a break-down into compounds of smaller radicals, as well as a sulphuration and also a mixe sulphuration and nitration so that there are ny by-products, in perhaps small quantities. Analysis has indicated-the presence of a sulphonic acid, a nitrosulphonic acid, phthalic acid, a nitrophthalic acid, and traces of sulphuric and nitric acids. There are probably other by-products as well, but at the present time we do not know that they have been isolated, although the presence of normal butaas sensitizers when these substances are synthetically mixed with pure nitronaphthalene which is made up into our blasting powder, al-

though they do not give as good a control over the sensitivity to explosion and the brisance or shattering power as may be had with the use of our special nitronaphthalene.

It is impossible to make a complete analysis of the result of the nitrating reaction to identify every entity present and to determine the quantity thereof. Whatever the desirable substance or substances is or are, it or they is or are present in the unwashed or incompletely washed nitronaphthalene and in the nitronaphthalene wherein the acidity calculated as sulphuric acid is washed down to /4 of 1%.

It is, of course, not desirable to leave absolutely unwashed the product of the nitrating reaction because the blasting powder made up with such material is apt to be dangerous.

The desired activating effect is perhaps not due merely to the acidity, that is, to a low pH, because the sodium salts of these activating materials seem to have an effect very similar to that of the acids. its broader aspects, therefore, includes the presence of by-products which have been neutralized, that is, salts of the acid radicals of such byproducts since these have some sensitizing value.

We have indicated certain variations from our specific disclosure which fall within the scope of our invention, but we prefer the specific procedure previously indicated.

Washing is best done with warm water, best under 95 F., as a matter of safety. It should, however, not be below the melting point of the oily layer in order not to solidify the oily layer during washing. The oily layer is washed therewith in any suitable manner as by dumping the water in on the orange-colored oil. The water efiects the separation of a scum which floats on top of the oil, and the washing is repeated to remove all of the scum. The scum looks something like a white lead mix-up for paint and is perhaps more cream-colored than pure white. It is a solid and not a liquid and is probably that indeterminate stuif usually obtained in an organic reaction.

After this oily layer has been Washed with hot water, cold water is contacted therewith which chills the oil into a solid of a color described as golden, and which is rather soft and has a greasy feel. When a piece thereof is pressed against a piece of paper with the finger, the body temperature apparently melts the solid since a grease stain then appears on the other side of the paper.

The nitronaphthalene made as above described is adapted for various uses. To make a blasting powder it is then compounded with picric acid and Chile saltpeter as follows: A steam-jacketed, copper kettle is heated with dry steam so that it will be at least slightly above the melting point of picric acid, namely, 122 C. (251.6 E); eight (8) pounds of the nitronaphthalene made as above described are placed in such heated ket- Our invention in another of 3 tle which results in melting the nitronaphthalene to an oil; thirty-three (33) pounds of picric acid (which may be the usual needle-like crystals hav- 7 ing therein the usual ten per cent. (10%) or three 3) pounds of water for purposes of safety, the same being equivalent to thirty pounds of dry picric acid) are added to the oil, care being taken not to stir since this may cause an explosion of the picric acid before it is dissolved. The picric acid dissolves. in the oil, and after such dissolution fifty-nine (59) pounds of about twenty-flveto fifty-mesh sodium nitrate are added, whereupon the steam is shut off and the mass is stirred or mixed for about forty minutes with a stirrer running at about twelve revolutions per minute, the result being a granular mass somewhat like com-meal. The sodium nitrate changes from white to yellow and appears to be no longer present as such. This granular mass is screened through a fourteen-mesh screen and large particles remaining on the screen may be broken up and put through again. The screened powder is spread out and subjected for about twenty-four hours to a temperature of about 100 F., which slowly removes moisture present therein, whereupon it is ready for use.

In the drying the corn-meal-like product is dried to less than one-half of one per cent. of moisture. It is loaded into cartridges of various sizes of the same types as prior standard blasting powders, and detonated likewise in the same manner.

The product so made is too fast for use in firearms, that is, the explosion thereof is too fast, and consequently its best use is for blasting; and it has nearly double the execution power, pound for pound, of present-day standard blasting powders at comparative prices. When the explosive is carefully made according to the above described process, it is quite stable and does not deteriorate with age. It will not freeze, nor will it explode when subjected to a bare fiame,-nor can it be exploded by impact, even by the impact of rifle and machine gun bullets. Adetonator is required to explode it and when it does explode, the explosion is flashless, even in the absence of light, and it produces no gases harmful or obnoxious to miners.

The proportions of the especially prepared nitronaphthalene, the picric acid and the sodium nitrate may be different from those described above; for example, eight (8) pounds of the nitronaphthalene, sixteen (16) pounds of the picric It is generally desirable to use sodium nitratesince there may be deterioration when some of the other nitrates are used, such deterioration sometimes inducing spontaneous explosions.

The corn-meal-like product above referred to, after it is dried, may be treated with a solution of parafiin in benzol, allowing the benzol to evaporate to coat the particles with paraffin, and we may thus produce a granular blasting powder each grain of which is waterproofed.

The especially prepared nitronaphthalene made as above described may be used otherwise than for making blasting powder; for example, it may be added to fuel for use in internal combustion engines with a resulting great increase in power without causing erosion or pitting of the engine. It may thus be added to gasoline at the rate of about one (1) ounce per gallon of gasoline.

The aqueous layer which results as a by-product of making the special nitronaphthalene has various uses. For example, a sun-proof paint can be made therefrom by adding to twenty-five (25) parts thereof, twent'y-flve (25) parts of ground silica, fifty (50) parts of lead pigment, and enough coloring matter to give the desired tint.

Our special nitronaphthalene may be used in combination with other nitrated compounds than picric acid. Nitrated organic compounds may be divisible into two groups; that is, the nitro bodies containing the NO: group, and the organic nitrates containing the N03 group, andas a general rule the nitro bodies when incorporated into our blasting powder as the equivalent of the picric acid are safer than the organic nitrates such, for example, as nitroglycerin, nitroglycol and nitrocotton (nitrocellulose). We class the organic nitrates as unsafe as a general rule since sometimes even slight degrees of acidity make the product too sensitive for safe handling,

.Whilewe have referred to certain details as being of importance, yet other details may be varied or changed without departing from the spirt of our invention the scope of which is defined in the appended claims.

Having described our invention, what we claim 1. The process which comprises adding fortyflve (45) avoirdupois ounces of flake naphthalene to one hundred (100) fluid ounces of 40 B. nitric acid and forty (40) fluid ounces of 66 B. sulphuric acid, maintaining the same at about 100 C., and washing out the resulting oily mass until the acidity is about A of 1% calculated as sulphuric acid.

2. The process which comprises adding fortyflve (45) avoirdupois ounces of flake naphthalene to one hundred (100) fluid ounces of B. to B. nitric acid and forty (40) fluid ounces of 66 B. sulphuric acid, maintaining the same at about 100 C., and washing out the resulting oily mass until the acidity is about A; of 1 calculated as sulphuric acid.

3. The process which comprises pouring one hundred (100) fluid ounces of 40 B. nitric acid into a vessel, after an interval pouring forty (40) fluid ounces of 66 B. sulphuric acid thereinto, heating to 100 C., adding forty-five avoirdupois ounces of flake naphthalene, maintaining said temperature until it is self-maintaining, allowing to stand until fumes are nd longer given off, and washing out the resulting oily mass until the acidity is about A, of 1% calculated as sulphuric acid.

4. The process which comprises pouring one hundred (100) fluid ounces of 35 B. to 40 B. nitric acid into a vessel, after an interval pouring forty (40) fluid ounces of 66 B. sulphuric acid thereinto, heating to 100 C., adding fortyflve (45) avoirdupois ounces of flake naphthalene, maintaining said temperature until it is selfmaintaining, allowing to stand until fumes are no longer given off, and washing out the resulting oily mass until the acidity is about A calculated as sulphuric acid.

5. A blasting powder consisting of picric acid,

an inorganic nitrate, and the product 01' the 5 process of claim 1.

6. A blasting powder consisting of picric acid, an inorganic nitrate, and the product of the process of claim 4.

7. A blasting powder consisting of picric acid,

1 an inorganic nitrate, and the product of the process of claim 2. 

